Hi all,
I was analyzing with Leela the variation posted below (3-4 high approach, 2 space high pincer, variation from joseki) and the final result was for me a complete shock: white loses a big corner, gets in compensation some thickness BUT leela states that the game is at least even, at best slight advantage for white.
1) Main question: Can you kindly give some explanation of Leela's final evaluation (even game) while for me is an easy resignation for white?
2) Secondary question: Can you check the line where it is not sound? (I checked tactical issues with leela but one cannot be 100% sure.)
as usual thanks in advance
Surprising result (imo) in 3-4 approach variation
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dfan
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Re: Surprising result (imo) in 3-4 approach variation
Take anything I say here with a kyu-sized grain of salt, but here are my thoughts:
1) Imagine that an equal number of White prisoners and Black stones-inside-territory have been removed (this doesn't change the score). Of course you have to realize that the resulting weaknesses in Black's shape aren't real. The board then looks like this.
Does that still feel as bad?
2) In the real game, after White plays B12, Black is going to have to actually take the White stones off the board, as the D16 group has only one eye. Even the G18 group may have to spend time making its two eyes. So that's a bunch of moves Black is going to have to play with no purpose other than to take stones off the board while White is getting even more thickness on the outside.
I don't know if it's actually a good rule of thumb, but by default I am happy with almost any sacrifice that my opponent has to actually remove from the board.
(By the way, Crazy Stone evaluates the position after
@ B12 to be 53% for White.)
1) Imagine that an equal number of White prisoners and Black stones-inside-territory have been removed (this doesn't change the score). Of course you have to realize that the resulting weaknesses in Black's shape aren't real. The board then looks like this.
Does that still feel as bad?
2) In the real game, after White plays B12, Black is going to have to actually take the White stones off the board, as the D16 group has only one eye. Even the G18 group may have to spend time making its two eyes. So that's a bunch of moves Black is going to have to play with no purpose other than to take stones off the board while White is getting even more thickness on the outside.
I don't know if it's actually a good rule of thumb, but by default I am happy with almost any sacrifice that my opponent has to actually remove from the board.
(By the way, Crazy Stone evaluates the position after
@ B12 to be 53% for White.)-
Gomoto
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Re: Surprising result (imo) in 3-4 approach variation
1. White has a clear advantage
Think:
for every captured white stone black needed to place a move as well
and white build a nice outside wall during this time
nice sacrifice strategy
2. Tactical unsound moves?
I never play the tactical unsound high approach of D15
(But your milage may vary).
Black B14 is a mistake and should be at H15.
I do not like white 1 (should be at 2) and a possible line for black is this: (black is better)
Think:
for every captured white stone black needed to place a move as well
and white build a nice outside wall during this time
nice sacrifice strategy
2. Tactical unsound moves?
I never play the tactical unsound high approach of D15
(But your milage may vary).Black B14 is a mistake and should be at H15.
I do not like white 1 (should be at 2) and a possible line for black is this: (black is better)
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sorin
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Re: Surprising result (imo) in 3-4 approach variation
I ran the final position with Leela, and it shows black as being ahead a little bit, having gained about 8% winrate, compared to the starting position.Fllecha wrote:Hi all,
I was analyzing with Leela the variation posted below (3-4 high approach, 2 space high pincer, variation from joseki) and the final result was for me a complete shock: white loses a big corner, gets in compensation some thickness BUT leela states that the game is at least even, at best slight advantage for white.
1) Main question: Can you kindly give some explanation of Leela's final evaluation (even game) while for me is an easy resignation for white?
So Leela agrees with you, white lost something in that exchange.
On the other hand, white built a lot of thickness on the outside, so the game is by no means over.
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Fllecha
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Re: Surprising result (imo) in 3-4 approach variation
Ok thanks sounds better now....
Last question: In the final position, left aside Leela's evaluation, with which side would you play?
Last question: In the final position, left aside Leela's evaluation, with which side would you play?
Don't play 1-2-3
Just play 3
(Go proverb)
Just play 3
(Go proverb)
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Gomoto
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Re: Surprising result (imo) in 3-4 approach variation
Sorry, I considered this position for white. (White ahead by a clear margin.)
Game is about even in your final position.
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sorin
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Re: Surprising result (imo) in 3-4 approach variation
I like black here, I agree with Leela's evaluation that black is ahead.Gomoto wrote:Sorry, I considered this position for white. (White ahead by a clear margin.) Game is about even in your final position.
The game is still very much playable for both sides though.
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Bill Spight
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Re: Surprising result (imo) in 3-4 approach variation
For tewari purposes, you have to realize that the weaknesses in Black's position are real.dfan wrote:Take anything I say here with a kyu-sized grain of salt, but here are my thoughts:
1) Imagine that an equal number of White prisoners and Black stones-inside-territory have been removed (this doesn't change the score). Of course you have to realize that the resulting weaknesses in Black's shape aren't real. The board then looks like this.
Does that still feel as bad?
Good point.2) In the real game, after White plays B12, Black is going to have to actually take the White stones off the board, as the D16 group has only one eye. Even the G18 group may have to spend time making its two eyes. So that's a bunch of moves Black is going to have to play with no purpose other than to take stones off the board while White is getting even more thickness on the outside.
Not a bad rule of thumb.I don't know if it's actually a good rule of thumb, but by default I am happy with almost any sacrifice that my opponent has to actually remove from the board.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
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Bill Spight
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Re: Surprising result (imo) in 3-4 approach variation
White has this sente. The average territory count remains the same. It would be interesting to see how Leela evaluates this position.
captures the 
stones and saves the 
stone. 
and 
may be played now or later.
10 stones of each player have been removed. White looks inefficient to me, considering the stone. Also, if White plays the dame, 
is inefficient.
saves the stones and captures the stone. 
and 
may be played later.
In this diagram 11 stones of each player have been removed. Black may be able to make something with regard to the stone.
Averaging the two tewari, Black looks more efficient.
captures the stones and saves the stone. and may be played now or later.10 stones of each player have been removed. White looks inefficient to me, considering the
stone. Also, if White plays the dame, is inefficient. saves the stones and captures the stone. and may be played later.In this diagram 11 stones of each player have been removed. Black may be able to make something with regard to the
stone.Averaging the two tewari, Black looks more efficient.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
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Bill Spight
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Re: Surprising result (imo) in 3-4 approach variation
I think I goofed with the tewari diagrams. White cannot afford to remove the White stone at G-15, as it gives too much play the Black stone at E-14.
OC, the stone would be better one space toward the corner.
In this diagram the
stone is plainly superfluous.
I think that the key to evaluating both diagrams is the assessment of the stone.
OC, the
stone would be better one space toward the corner. In this diagram the
stone is plainly superfluous. I think that the key to evaluating both diagrams is the assessment of the
stone.The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
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sorin
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Re: Surprising result (imo) in 3-4 approach variation
Oh, I see - sorry! I thought it is the same position.Gomoto wrote:Be careful, in this position (not the OP's position) winrate for black is only 43%
In your position, it is as if white has pushed one more time on the 3rd line, and black replied on the 2nd, I see - that must be a gain for white compared to OP's position.
Also, to the tewari analysis dfan posted: one cannot just remove a cutting stone from the "outside" of the position; for tewari purposes, only dead/inert inside stones are usually cancelling each other out and can be removed.
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dfan
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Re: Surprising result (imo) in 3-4 approach variation
Thanks (and also to Bill Spight). I didn't know there were rules for this sort of thing (I'm only familiar with tewari in the sense of reordering moves), so it's just a heuristic I use to get a better sense of how many points a capture is worth, since often it looks worse than it is.sorin wrote:Also, to the tewari analysis dfan posted: one cannot just remove a cutting stone from the "outside" of the position; for tewari purposes, only dead/inert inside stones are usually cancelling each other out and can be removed.
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John Fairbairn
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Re: Surprising result (imo) in 3-4 approach variation
I found this thread fascinating but alarming as to what it says about amateur go.
As an amateur I have no definitive ideas either, but trying to apply some pro insights I get the same result as Leela - slightly favouring White.
First the tewari as done here seems dubious to me. Even Bill's. I'm at a natural disadvantage here as the position needs more fingers than I've got, but in tewari (ii) I don't see how you can justify ending up with a position where locally both sides have the same number of stones but Black has one more stone on the board as a whole, whereas in the game they have played an equal number of stones overall.
Next, applying the pro rule of thickness being worth (n * n+1)/2 with n being the length of the wall (but not usually counting stones on the edges - the rule of each stone in a wall being worth 3 points is an approximation of this for the commonest lengths of wall). On that basis I assume a wall of 8 gives White about 36 points, with an averaged few extra points for the late boundary plays on the upper left side. Black has just over 20. Since Black as an extra stone elsewhere on the board which can be counted as 15 points, White has significant advantage. It's true that the cutting black stone at E14 will possibly have some influence (e.g. Black can maybe make a good play around the point), but there is a case for saying White's wall could be counted as 9 (giving 45 points), so I'd assume these two things balance out.
I'm also very dubious about White D6. Thickness is not thickness unless it functions as thickness. That means attacking. This D6 is a pure gote defence move and smacks of overconcentration and of thinking only of territory. You make territory in the region of thickness by surrounding it dynamically, i.e. by attacking and keeping sente. A positive attitude such as F5 or a pincer seems called for here.
As an amateur I have no definitive ideas either, but trying to apply some pro insights I get the same result as Leela - slightly favouring White.
First the tewari as done here seems dubious to me. Even Bill's. I'm at a natural disadvantage here as the position needs more fingers than I've got, but in tewari (ii) I don't see how you can justify ending up with a position where locally both sides have the same number of stones but Black has one more stone on the board as a whole, whereas in the game they have played an equal number of stones overall.
Next, applying the pro rule of thickness being worth (n * n+1)/2 with n being the length of the wall (but not usually counting stones on the edges - the rule of each stone in a wall being worth 3 points is an approximation of this for the commonest lengths of wall). On that basis I assume a wall of 8 gives White about 36 points, with an averaged few extra points for the late boundary plays on the upper left side. Black has just over 20. Since Black as an extra stone elsewhere on the board which can be counted as 15 points, White has significant advantage. It's true that the cutting black stone at E14 will possibly have some influence (e.g. Black can maybe make a good play around the point), but there is a case for saying White's wall could be counted as 9 (giving 45 points), so I'd assume these two things balance out.
I'm also very dubious about White D6. Thickness is not thickness unless it functions as thickness. That means attacking. This D6 is a pure gote defence move and smacks of overconcentration and of thinking only of territory. You make territory in the region of thickness by surrounding it dynamically, i.e. by attacking and keeping sente. A positive attitude such as F5 or a pincer seems called for here.
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Gomoto
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Re: Surprising result (imo) in 3-4 approach variation
I refuse to enter the B15 E18 exchange 
Zen 7 white D6 (best move according to Zen) winrate for black 44% Zen 7 white F5 winrate for black 46% Zen 7 white J4 winrate for black 46% Zen 7 white H3 winrate for black 48%
Zen 7 white D6 (best move according to Zen) winrate for black 44% Zen 7 white F5 winrate for black 46% Zen 7 white J4 winrate for black 46% Zen 7 white H3 winrate for black 48%
Last edited by Gomoto on Tue Jan 09, 2018 7:26 am, edited 1 time in total.